EEG Rhythms - Event-Related Desynchronization and Synchronization

Abstract

Event-related desynchronization (ERD) designates a short-lasting and localized amplitude attenuation of rhythms within the alpha band; event-related synchronization (ERS) describes a short-lasting amplitude enhancement. The topographical pattern of the ERD may reflect activation or excitation of cortical areas. Localized patterns of ERS probably represent inhibition of cortical areas. During a visual· task, ERD is .~ou?d over occipit~l areas and ERS over central areas close to the electrodes C3 and C 4. InttInsic rhythIl,ls WIthm the alpha band can therefore be used to study excitation and Inhibition or idling of cortical areas.